Origin

The word dog appears only once in surviving Old English literature, and until the Middle Ages hound was the ordinary word for a dog. The low status of dogs is shown by phrases like a dog's life, not have a dog's chance, and to treat someone like a dog. For something to go to the dogs is certainly undesirable, but even such luckless animals might sometimes get hold of a tasty treat or a warm bed, for every dog has its day. Dogs can be savage, and dog eat dog signifies a situation of fierce competition. This rather chillingly makes reference to, and reverses, the proverb dog does not eat dog, which dates back to the mid 16th century in English and has a precursor in Latin canis caninam non est, ‘a dog does not eat dog's flesh’. Every dog is allowed one bite is based on the rule, probably dating from the 17th century, by which an animal's owner was not liable for harm done by it unless he knew of its vicious tendencies. A dog in the manger, ‘a person inclined to prevent others having or using things that they do not want or need themselves’, derives from a fable in which a dog lies in a manger to prevent the ox and horse from eating hay. People have invoked the idea since the 16th century. A change in the status of dogs is found in the idea of the dog being man's best friend, which seems to be a Victorian one, a change emphasized by love me, love my dog. See also bollock, canary, dinner, hair, havoc